81118201 has 4 divisors (see below), whose sum is σ = 85387600. Its totient is φ = 76848804.

The previous prime is 81118199. The next prime is 81118207. The reversal of 81118201 is 10281118.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81118201 - 2¹ = 81118199 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81118207) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2134671 + ... + 2134708.

It is an arithmetic number, because the mean of its divisors is an integer number (21346900).

Almost surely, 2^81118201 is an apocalyptic number.

It is an amenable number.

81118201 is a deficient number, since it is larger than the sum of its proper divisors (4269399).

81118201 is a wasteful number, since it uses less digits than its factorization.

81118201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4269398.

The product of its (nonzero) digits is 128, while the sum is 22.

The square root of 81118201 is about 9006.5643283108. The cubic root of 81118201 is about 432.8852321852.

Adding to 81118201 its reverse (10281118), we get a palindrome (91399319).

The spelling of 81118201 in words is "eighty-one million, one hundred eighteen thousand, two hundred one".